Cannot get the value of jQuery Spinner by $_POST in php

Cannot get the value of jQuery Spinner by $_POST in php

I am using jQuery Spinner in a form just like Select Option.

$("#hourlywage").spinner({ min: 50, max: 1000, step: 10, start: 50, culture: "en-US", numberFormat: "C" });

After submitted the form, I can get value from Select Option by $_POST['select'].

However, there is nothing in the value of Spinner get by $_POST['hourlywage'].

Is there anything I have missed or the method is wrong?